Print impression mechanism



Nov. 20, 1956 H. J. KISTNER E TAL PRINT IMPRESSION MECHANISM 2 Sheets-Sheet 1 Filed Nov. 2, 1953 INVENT OR. HAROLD J. KISTNER OTTO F'. MONEAGLE ATTORNEY Nov. 20, 1956 H.J..K|STNER ETAL 2,771,025

PRINT IMPRESSION MECHANISM Filed Nov. 2, 1955- 2 Sheets-Sheet 2 FIG. 2

W m OOOOOOw 000000 0000000 0000000 AHWOOMWOOO owwowww CODE ROD FRAME 21 INVENTOR. HAROLD J. KISTNER PRINTING WIRES SET-UP BAIL\ 0 CODE ROD NON-PRINTING WIRES RESTORING BAIL 14 PLATEN\ PRINTER HEAD.

FIG. l

OTTO E MONEAGLE J TTORNE 1' United States PatentO PRINT IMPRESSION MECHANISM Harold J. Kistner and Otto F. Moneagle, Endicott, N. Y.,

assignors to International Business Machines Corporation, New York, N. Y., a corporation of New York Application November 2, 1953, Serial No. 389,621

4 Claims. (Cl. 10193) terns has been suggested heretofore, e. g., in U. S. Patent 2,524,127 issued to Reynold B. Johnson. Most prior art printers of this class involve the use of print wire setting devices against which one end of the Wires rests or with which the Wires are otherwise positively engaged during the printing stroke. It is, therefore, a common characteristic of these printers that the print wires are held against longitudinal movement during the printing operation. This fact may afford poor quality printing because it presupposes that all of the print wires are exactly of the same effective length and that all of the wire ends thereof forming a character pattern are moved into the same printing plane by their individual setting devices. Although these conditions are theoretically possible, they are very diflicult to achieve in practice. The'invention disclosed in U. S. Patent No. 2,730,040, which issued on January 10, 1956, to Reynold B. Johnson, overcomes the aforesaid difliculties by providing for the controlled longitudinal movement of print wires under impact of the printing stroke so that the force of the printing stroke is itself effective to align the wire ends of the character pattern forming wires in a common printing plane.

In order to produce not only legible printing but good quality printing as well, particularly when multiple record sheets are produced simultaneously under impact of each printing stroke, a sufficient value of energy is required at the time of impact. If the value of impact energy is too low in a printer such as described in the aforementioned patent application, the wire ends forming the character pattern will be moved slowly in a longitudinal direction under impact of the printing stroke, whereupon a poor quality character imprint will result. On the other hand, if the value of impact energy is too high, the record sheet, or sheets, upon which the characters are printed will be damaged. As the value of impact energy is determined by the kinetic energy of the print impression mechanism, and since kinetic energy is equal to one-half the product of mass and velocity squared (K. E.= /2mv. it is apparent that the impact energy may be varied by changing either the mass of the character print wires or the velocity of the print wires during the printing stroke. It is usually advantageous to increase the velocity rather than the mass because utilization of low mass character forming print wires permits the use of a low force to set up. the same since force is equal to the product of mass and acceleration (F=ma). In

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addition thereto, the use of a-small mass and a low force permits the use of comparatively small machine parts which improves the noise factor of the printing machine considerably.

A principal object of this invention is to provide an improved print impression mechanism for printing machines.

In line with the foregoing, another object of this invention is to provide a print impression mechanism for wire printers for printing impressions, whether of a single character or a plurality of aligned simultaneously imprinted characters, of uniformly good quality.

A specific object of this invention is to provide a wire printer having a movable platen and a coacting movable printer head.

Other objects of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of examples, the principle of the invention and the best mode, which has been contemplated, of applying that principle.

In the drawings:

Fig. 1 is a somewhat diagrammatic sectional view of a wire printer that embodies the features of this invention. This view illustrates a print wire assembly and a print impression mechanism for a single character position.

Fig. 2 is a fragmentary view of a printer head showing the print wires of a cluster of wires displaced to form the letter L.

Fig. 3 is a diagram, on an enlarged scale, of the letter L, adapted to be formed by the character pattern print wires.

Fig. 4 is a timing diagram.

In view of the fact that the instant invention is an improvement over the invention described in the aforementioned Johnson patent, reference will be made thereto wherever possible in order to avoid undue prolixity.

' WIRE PRINTING-GENERAL The. wire printing mechanism described herein forms characters from a closely spaced pattern of dots as shown in Fig. 3. Each dot is marked on a record sheet when the end of a print wire is pressed against an inking ribbon adjacent the record sheet. A generally rectangular cluster of sixty-three print wires, each having a very small diameter, e. g., 009 inch, is used at each printing stations Each cluster has its wires arranged in seven vertical rows of nine wires each. Informing a character pattern corresponding to the character to be printed, various print wire combinations are moved outwardly a short :distance so that their ends protrude slightly beyond the base of the cluster. These protruding wires which form the character pattern cause the aforementioned dots to be imprinted on the record sheet so as to form the desired corresponding character. 7

Formation of the characterpattern involves selection of the proper print wires to be projected to form the character pattern. As the meansrnecess-ary to form the character pattern on the printer head is not a part of the instant invention, and since this means is described in detail in the aforementioned R. B. Johnson patent application,- for clarity and brevity of description it will be described only briefly herein.

Referring to Fig. 1, the sixty-three print wires 10 form a rectangular cluster at printer head 11 (see Fig. 2), and from this cluster the print wires are fanned out in a series of guides in .a print wire bail 12 to form a single line of wires at relatively large spacing at the other or controlv end 13. Attached to the controlend of each print wire '10, and positioned between the restoring bail 14 of print wire bail 12 and a stop comb '1'5,is a print wire slug 16 having a weight, for example, of one gram.

Furthermore, each of the print wires is arranged ing 17 is attached to printer head 11 in a close rectangular formation for movement therewith (see Fig. 2), and the other end of each tubular casing is fixed to a stationary tubular casing guide bar 18.

Print wire bail 12 is reciproca-ted by cams 19 and 20, whereupon slugs 16 are brought into alignment with nonmovable stop comb during the downward movement of bail 12. Adjacent the control end 13 of each print wire 10, and positioned within a code rod frame 21 attached to bail 12 is a code rod 22 which has a diameter, for example, of .093 inch. There is one such code rod for each printing position. As described fully in the aforementioned patent application, a pattern of notches is cut transversely across each of four sides of the code rod. Hence, by rotating the code rod in increments of 90, four separate groups of notches can be presented to the control ends 13 of the print wires. The arrangement of each code rod 22 and associated control mechanism is such that as code rod 22 is moved by code rod frame 21 into contact with the control end 13 of print wires 10 by earns 19 and 20, the code rod will have no effect on a given print wire 10 if the control end of the print wire enters a notch in the code rod. If, however, control end 13 of a print wire 10 strikes a high portion of code rod 22, the print wire will be moved within its tubular casing17, and, accordingly, its wire end will protrude above the general level of the cluster of wires at the printer head.

If, for example, it is desired to arrange the print wire ends at printer head 11 to any one of forty-eight different character patterns, each character pattern corresponding to an alphabetic, numeric or special symbol character, it is necessary to present forty-eight different sections of code rod 22 to the control ends 13 of print wires 10. As mentioned hereinbefore, code rod 22 may be rotated in increments of 90 to four different positions. It now follows that the aforementioned forty-eight different code rod sections may be obtained by shifting code rod 22 longitudinally to each of twelve index positions. Code rod 22 is biased to a normal position (to the left) by means of a spring 23. This spring permits longitudinal movement of the code rod as well as the necessary rotary movement during adjustment into .a given wire setting position whereupon a character pattern is formed.

The longitudinal movement of print wires 10 during set up and restoration thereof is limited and stabilized by print wire attached slugs 16. Each slug, in effect, constitutes an inertia device which is overcome by impact of the printing stroke for normalizing at the printing zone the protruding print wire ends of a character pattern in a common printing plane during the printing stroke.

It was stated previously that print wires '10 are relatively free to move longitudinally under imp-act of the printing stroke. Reference to Figs. 1 and 4 will show why this is true. At 270, cams 19 and have rotated so as to carry code rod frame 21, and consequently code rod 22, out of contact with the control ends 13 of print wires 10, and align slugs .16 along stop comb 15. This so-called restored position is achieved by movement of restoring bail 14 under influence of .cams 19 and 20, during which movement restoring bail 14 engages the print wire attached slugs 15 and moves said slugs into proximity with the flange of stop comb 14. This action also aligns the control ends 13 of the print wires.

At approximately 90 of the printing cycle, the parts will assume a so-callcd setting up position. At this time the cams '19 and 20 have carried restoring'bail. 14 upwardly and out of contact 'withslugs 16. At the same time, code 'rod frame 21 is moved upwardly sothatcode rod 22 engages the control ends 13 'of print wires 10,

thus setting the print wires in a selected character pattern printing position.

'At approximately of the print cycle, just prior to print time, cams 19 and 20 have moved code rod frame 21 and consequently code rod 22 downwardly so that none of the print wire control ends 13 are in contact with the code rod, and none of the slugs 16 are in proximity to stop comb -1-5. This permits freedom of movement in a longitudinal direction of the print wires under impact of the printing stroke.

Hence, movement of code rod 22 sets up print wires 10 so as to form a character pattern between 0 and 180 of the printing cycle. As is shown in Fig. 4, code rod 22 engages control ends 13 of print wires 10 at approximately 25 of the printing cycle. As described in the aforementioned copending U. S. patent application, and as is shown in Fig. 4, the code rod set-up bails (bails, not shown, for applying a rotary and a longitudinal movement to the code rod) are effective during the latter half of a printing cycle, i. e., from 180 to 360, so as to set up the code rod for the following printing cycle.

PRINT IMPRESSION MECHANISM The present invention is embodied in the improved structure of the print impression mechanism which will now be described.

Referring to Fig. 2, tubular casings 17 are secured one to the other, and to printer head 11, so that as cam follower arm 24 (Fig. 1) is caused to oscillate about pivot 25, printer head 11 including the tubular casings is caused to reciprocate accordingly in a longitudinal plane. Due to the frictional engagement between each print wire 10 and its respective tubular casing 17, this reciprocating movement of printer head 11 does not of itself cause a relative movement between a print wire 10 and its respective tubular casing 17. In other words, print wires displaced at the printer head to form a character pattern such as the letter L shown in Fig. 2, will remain so displaced and will not be affected by the movement of the printer head per se.

A striker roller 26 is rotatably connected to a stud attached to a striker roller arm 27 which, in turn, is fixed to striker assembly gear 28 through a stud shaft 29 for rotating the aforesaid integral unit. A somewhat resilient steel band platen 30 is supported between striker roller 26 and printer head 11 by a pair of platen guides 31 and 32. Platen 30 is attached at each end to a corresponding platen support 33 and 34 by locking screws 35. It is to be observed that since platen supports 33 and 34 are freely mounted on rods 36 and 37, respectively, the tension of platen 30 may be changed by varying the position of adjusting screws 38.

The record sheet, or record sheets, upon which the characters are imprinted, are positioned between platen 30 and inking ribbon 39 which, in turn, is positioned adjacent printer head 11.

Cam 39 is attached to printer headgear 40 which is caused-to rotate by any suitable driving means, as is gear 28, so that printer head 11 is caused to reciprocate as cam 11. This action of platen 30 moves the record sheet accordingly in a direction towards printer head 11. Hence, even though the printer head may be operated at a low or intermediate printing speed, the high velocity movement imparted to platen 30 as a result of engagew After code rod 22 has been set up so a'sto' cause print "wires10 associated therewith to be set up correspondingly in a manner described hereinbefore, the selected 'print wire ends at the printer head are caused to project a distance, e. g., .030 inch, to forma character pattern. Referring once again to Fig. 4, these wire endsare caused to so protrude during the time interval between and 90 of the printing cycle while printer head 11 is just beginning to move toward platen 30. During the period 0 to 180, platen 30 receives two blows as a result of byprinter'head 11 so that as striker roller arm 27 rotates to sweep striker roller 26 past platen 30, a print impression is obtained. It is to be observed that the'protruding character pattern forming print wire ends are struck a percussive blowby platen 30 which is 'sufiicient to cause a longitudinal movement of these print wires so as to align the ends of the character pattern forming wires in a common printing plane. As is shown in Fig. 4, these print wires 10 are actually caused to move beyond the common printing plane to some indefinite position. i The print wiresare thereafter restored to a home position within printer head 11. This occurs duringthe period between print time and !270 by the aforedescribed action of restoring bail 14 (Fig. 1) upon slugs 16. Itwill be recalled that restoring bail 14 at this time is moved downwardly by cams 19 and so as to align the; print Wire attached slugs against stationary stop comb 15.

Print suppression Print suppression may be selectively controlled automatically or manually. Automatic print suppression may be had by energizing print suppression magnet coil 43 shown in Fig. 1, which thereupon attracts armature 44. This action moves connecting link 45 downwardly and pivots print suppression lever 46 in a clockwise direction, whereupon lever 46 engages the cam follower arm extension 47 "of cam follower arm 24. Hence, cam follower roller 41 is prevented from riding on cam 39 and printer head 11 is kept without the printing zone. This positions the character pattern forming print wires away from moving platen so as to preclude printing.

Manual print suppression may be had by moving lockout lever 48 in a counterclockwise direction about pivot 49 so that dog 50 enters notch 51 inprinter head 11. This engagement also keeps printer head 11 outside of the printing zone. Lockout lever 48 is maintained in a set position by the engagement of spring biased ball 52 and an associated detent in the said lever.

SUMMARY With particular reference to Figs. 1 and 4, code rod 22 is set up during the period between 180 and 360 so as to be positioned to correspondingly set up selected print wires 10 during the immediately following 0 to 90 period. This print wire setting causes a character pattern to be formed at printer head 11. This character pattern is depicted by print wires 10 protruding from their respective tubular casings 17 which are secured, at one end, to printer head 11 and, at the other end, to stationary tubular casing guide bar 18. During the time interval between 0 to 180, printer head 11 is moved toward platen 30 under control of cam follower roller 41 and cam 39. Since striker roller 26 moves in a path concentric to shaft 29 and at an angular velocity five times that of cam 39, at print time, i. e., approximately 180, platen 6 30 is moved within the printing zone now occupied by printer head 11. This action effects printing upon the record sheet positioned between printer head 11 and platen 30. The ,print impressions obtained on the record sheet, or record sheets, are of uniformly good quality because of the longitudinal movement of print wires 10 to a common printing plane under impact of the printing stroke, and the correct value of impact energy accorded by the high velocity platen 30. During the time interval between print time and 360", printer head 11 is removed from within the printing zone and print wires 10 are restored to their normal position under control of restoring bail 14. During this period, code rod 20 is set up for the next printing cycle. The impacts accorded platen 30 during this time by the moving striker roller 26 are of no'etfect because printer head 11 is without the printing zone.

While there have been shown and described and pointed out the fundamental novel features of the invention as applied to a preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art, without departing from the spirit of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the following claims.

What is claimed is:

r l. A print impression mechanism of the class described in. a cyclically operable printer for printing characters on a record sheet comprising a movable printer head having a cluster of loosely held print elements arranged so that the ends thereof define a character pattern at a printing face, a movable platen, means for moving said printer head towards and away from said platen once each printer cyclefat a rate of speed insuflicient to provide value of printing stroke energy which is suflicient to effect good quality printing, and means for simultaneously therewith moving said platen towards and away from said printer head aplurality of times each printer cycle at a rate of speed insufiicient to provide a value of printing stroke energy which is sufiicient to effect good quality printing, said moving means effectively moving said printer head and said platen simultaneously into a common printing zone once each printer cycle to cause said loosely held print elements and said platen to simultaneously engage the record sheet positioned in the printing zone between the printing face of said printer head and said platen, Whereby the ends of said loosely held print elements are aligned by the impact of the aforesaid engagement in a common printing plane at a value of printing stroke energy which is sufficient to eifect a good quality print impression of said character pattern on the record sheet.

2. In a cyclically operable wire printer, the combination of a print impression mechanism of the class described, print -Wires each having a print end and a control end, a movable printer head wherein the print ends of said print wires terminate in a common plane, a movable platen, means for differentially positioning the control ends of selected ones of said pnint wires to move the print ends thereof relative the common plane so as to define a character pattern at a printing face, means for loosely holding the ones of said print wires defining the character pattern at the printing face so that the print ends thereof are frictionally movable relative the common plane, means for moving said printer head towards and away from said platen once each printer cycle at a rate of speed insuflicient to provide a value of printing stroke energy which is sufiicient to effect good quality printing, and means for simultaneously therewith moving said platen towards and away from said printer head a plurality :of times each printer cycle at a rate of speed insufficient to provide a value of printing stroke energy which is sufiicient to effect good quality printing, whereby said moving means efiectively moves said printer head and said platen simultaneously toward one another once each printer cycle so that the print ends of said print wires at the. printing -face engage one side of a record sheetat the same time the other side thereof engages. said moving platen, :the impact of the printing stroke effecting a movement of the print ends of the ones of said print wires defining the character pattern so as to align the aforesaid print ends in a common printing plane. at a value .of printing stroke energy which is sufiicient to etfect good quality printing on the record sheet.

3. In a cyclically operable Wire printing machine for printing characters on a record sheet, a print impression mechanism comprising a plurality of print wires each having a print end and a control end, a corresponding plurality of print wire casings within each of which respective print wires are ftictionally engaged, a movable printer head to which said casings are secured so that the print ends of said print wires terminate in a common plane, means operable on the, control ends. of said print wires for actuating selective ones of said print wires to move the same within their respective casings so that the print ends thereof form a character pattern at. a printing face, said actuated print wires being maintained in a character pattern position by the frictional engagement between each print wire and its respective print wire casing, a movable platen, means for moving said platen into a printing zone a plurality of times each machine cycle and at a rate of speed insufficient to provide a value of printing stroke energy which is suflicient to effect good quality printing, and means for moving said printer head into the printing zone once each machine cycle and at a rate of speed insufficient. .to provide a value of printing stroke energy which. is sufiicient to effect good quality printing, said printer head and said. platen moving means causing said printer head and said platen to be moved simultaneously into the printing zone once each machine cycle, whereby the pnint. ends of said print wires forming a character pattern and said platen engage during the simultaneous movement thereof to provide a value of printing stroke energy which is sufiicient to effect 8 good quality printing onthe record sheet of the character pattern at the printing face.

'4. In, a wire printing machine for printing characters von a record sheet, a print impression mechanism comprising a plurality of print wires; a corresponding plurality ofpr-int wire casings within each of which respective print wires are frictionally engaged; a movable printer head to which said:casings are secured so that said print wires terminate at one end in a common plane to constitute a printing face; a movable platen including a resilient band, a rotatable arm, and a striker roller attached to one end of said arm for imparting a percussive stroke to said band once for each rotation of said arm so as to move said band into a printing zone; means for rotating said arm; means for actuating selected ones of said print wires to move the same within their respective casings relative to thecornmon plane in order to form a character pattern at the printing face; and means operative in a timed relation to said arm rotating means for moving said printer head into the printing zone so that said band and. the ends of said print wires forming the character pattern effect a print impression of the character pattern on the record sheet.

References Cited in the file of this patent UNITED STATES PATENTS 

